Noone has 2.1 running on the M001 yet, and the speculation I've seen is that it doesn't have the RAM (128Mb) or enough graphics acceleration to do it well.

I was thinking about trying it myself, but I mostly bought it to put debian on it, and remove the board to use it as a robot controller. Not to mention that the Android build process looks tricky and extremely device-specific, from what I've seen :).

Have you managed to put debian on it?

At this price, these prebuilt tablets are much cheaper than attempting to build something from the ground up(as with BeagleBoard which admitedly runs a much more powerful CPU)

No Debian yet, all I've done so far is put in a serial console to watch it boot (only had it 3 days.)

There's a photo of it running debian here, and some details for running debian on another device with the same SoC architecture (WM8505): http://slatedroid.com/index.php?topic=152.0

The easy way is undoubtedly to use debootstrap and keep the current kernel it's running. I think that's more or less an easy and given possibility, because once you have the serial port connected you have a root console (or presumably you can unlock root access in software via Android.)

Building a kernel as well may be harder. From what I can tell, and it's hard to tell because most people (including Eken) aren't releasing source at the moment (sigh), this may be hard because of a bunch of proprietary M8505 modules in the current kernel. Not sure yet, though.

Over the BeagleBoard (and like), the appeal for me (given I'm ditching the screen) is that I don't live in the US. The price of the BeagleBoard plus shipping to Australia makes a big difference.

The M001 is $99 including shipping anywhere in the world.

Heck, I'm not even sure I can find just the display for these prices.

I would think 2.2 might be appealing, though, given the substantial speedups some people have reported with it. Assuming those come from improved efficiency in the VM, that would be of most benefit to the weakest processors. There's nothing I can see from the CDD that suggests that at least 2.1 wouldn't be supported on these devices, even with limited (or no) graphics flare.

You're correct, I believe 2.1 will run on the same kernel it currently has, albeit sans graphical acceleration.

IIRC, 2.2 will at minimum require someone to build a newer kernel, which AFAIK noone has worked out how to do (see my post above about proprietary WM8505 modules.)

It's hard for a noob like me to work it all out though, because almost noone is releasing any source or doing their development work in public (I intend to post anything useful that I figure out.)